GB1591931A

GB1591931A - Connection of a submarine conduit to a submarine pipe

Info

Publication number: GB1591931A
Application number: GB10191/78A
Authority: GB
Original assignee: Compagnie Generale Pour Les Developpements Operationnels Des Richesses s Ous Marines C G Doris
Current assignee: Compagnie Generale Pour Les Developpements Operationnels Des Richesses s Ous Marines C G Doris
Priority date: 1977-03-18
Filing date: 1978-03-15
Publication date: 1981-07-01
Also published as: IT1092850B; IT7820755A0; US4254728A; ES467475A1; NO149744C; BR7801668A; NO780912L; FR2384192A1; CA1075021A; NO149744B; FR2384192B1

Description

PATENT SPECIFICATION

_ 1 ( 21) Application No 10191/78 M ( 31) Convention Application No.

C> 7708 19 ( ( 33) C ( 44) A) ( 51) ( 52) ( 72) ( 11) 1 591 931 ( 22) Filed 15 March 1978 ( 32) Filed 18 March 1977 in France (FR) Complete Specification published 1 July 1981

INT CL 2 F 16 L 1/00 Index at acceptance F 2 G 8 Inventor JEAN-FRANCOIS PATINET ( 54) CONNECTION OF A SUBMARINE CONDUIT TO A SUBMARINE PIPE ( 71) We, COMPAGNIE GENERALE POUR LES DEVELOPPEMENTS OPERATIONNELS DES RICHESSES SOUS-MARINES " C G DORIS," a French Body Corporate, of 83-85, Boulevard Vincent Auriol, 75013 Paris, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:-

The invention relates to a device for use in, and a method of, connecting a submarine conduit to a submarine pipe.

Theoretically, the connecting of a submarine conduit to another conduit or to, for example, a storage tank presents no difficulty Nevertheless, in practice, problems arise In fact, in spite of all precautions taken, it frequently happens that deviations occur with regard to the predicted direction and distance Deviations regarding direction only present slight inconvenience but distance deviations are more serious If, for example, the conduit is intended to connect a well to a storage tank, the tank, which consists of a large volume construction sometimes submerged at a considerable depth, cannot be located with great precision from the surface To deal with these difficulties, French Patent Specification No 2,093,171 proposes a device consisting of a semi-circular collector fixed to the wall of the tank This collector carries, at specified spacings, branches allowing connection at whatever position thc conduit arrives A belt consisting of two rails parallel to each other and to the collector is fixed on the tank and allows the movement of a cradle on which the arriving end of the conduit is fixed The cradle supporting the conduit is then fixed with the aid of bolts and connection elements are arranged between the conduit and one of the branches of the collector The number and the length of these elements is selected in a manner to bring about an exact connection to one of the branches of the collector The various positioning operations of the cradle and the connecting operation have to be carried out by divers.

While this solution is suitable for connections at shallow depth, the above described device cannot be used when great depths are reached In fact, it is then out of the question to use divers and the lack of pre 55 cision of operating at great depths does not permit, with known devices, the use of connection tubing or pins of standard dimensions.

The object of the invention is to devise 60 a mooring and connecting device permitting the mooring of the end of a submarine conduit at an exactly specified distance in relation to the end of another conduit occupying a definite position and the con 65 necting of the ends of the two conduits by a standard junction pipe.

According to one aspect of the invention, there is provided a device for use in coupling a submarine conduit to a sub 70 marine pipe, which device includes a mooring frame having a support column and a fastening hollow arm mounted on the column so as to be pivotable about the longitudinal axis of the column, and a 75 mooring head adapted to be attached to the end of the conduit to be coupled to the pipe and to be drawn by a cable into the hollow arm, the hollow arm serving to automatically fasten the mooring head 80 to the frame after taking up the position of least resistance to the cable.

Preferably the hollow arm has a cylindrical axial bore and the mooring head is substantially cylindrical and is adapted to 85 fit within the bore The hollow arm may include a stop for positioning the mooring head at a predetermined distance from the support column Furthermore the hollow arm may be provided with locking means 90 passing through a wall thereof for locking the mooring head within the hollow arm.

The positioning means may be provided on the mooring head and the hollow arm for ensuring a particular orientation of the 95 mooring head within the hollow arm Advantageously the positioning means comprises a longitudinal slot in the hollow arm and a projection on the mooring head adapted to fit within the longitudinal slot 100 1 591 931 The moring head may be provided with expandable means for fixing the mooring head to a towing cable, and the hollow arm may be provided with cable guidance means for guiding the mooring head towing cable from the inside to the outside of the hollow arm.

The junction duct may be in the shape of an inverted U and may comprise connectors for connecting together the conduit and pipe under hydraulic control.

According to another aspect of the invention, there is provided a method of coupling a submarine conduit to a submarine pipe, which method comprises attaching a moring frame having a support column to the pipe such that the pivot axis of a fastening hollow arm mounted on the column so as to be pivotable about the longitudinal axis of the column is coaxial with the end of the pipe to which the conduit is to be coupled, attaching a mooring head to the end of the conduit to which the pipe is to be coupled, and drawing the mooring head into the hollow arm by means of a cable coupled to the mooring head, the hollow arm automatically taking up the position of least resistance to the cable.

The method may further comprise connecting the conduit and the pipe by means of a junction duct Preferably the cable is passed over cable guiding means on the hollow arm.

In one embodiment, a towing cable is attached to the mooring head, a hauling cable is passed over the cable guiding means, one end of the hauling cable emerging from the end of the hollow arm adapted to receive the mooring head, the two ends of the hauling cable are held on the surface, the towing cable is attached to said one end of the hauling cable on the surface, the hauling cable is hauled by a winch until the towing cable reaches the winch, and the towing cable is then used to draw the mooring head into the hollow arm.

In an alternative embodiment, a hauling cable is passed over the cable guiding means, one end of the hauling cable emerging from the end of the hollow arm adapted to receive the mooring head, the two ends of the hauling cable are held on the surface, and the hauling cable is attached directly to the mooring head and used to draw the mooring head into the hollow arm.

The following description, given by way of example, allows a full understanding of how the invention can be carried out, reference being made to the accompanying drawings in which:

Figure 1 is a side view, partly in section, of a device according to the invention, and Figure 2 is a plan view of the device of Figure 1.

In the embodiment of the invention shown in Figures 1 and 2, the conduit is shown moored but not yet connected.

A submarine conduit 1, which is kept in hydrostatic equilibrium by a system comprising a float 2 and a guide rope 3, carries 70 on its end which is to be connected, a mooring head 4 This mooring head consists of a cylindro-conical body 5 fixed coaxially to the conduit According to the embodiment shown, the conical end 6 is welded 75 to the periphery of the conduit, a centring device 7 being arranged in the cylindrical part A peripheral opening is provided for the connection end of the conduit This opening is provided by welding a collar or 80 ferrule 8 on to an aperture provided in the wall of the cylindrical body The angle formed by the collar with respect to the axis of the mooring head 4 will depend on the final slope of the mooring head and 85 will, for preference, be such that the axis of the ferrule, and consequently the end 9 of the conduit 1, is vertical The end 9 of the conduit is kept co-axial to the ferrule by passing through a flange 10 welded to 90 the ferrule 8 and to the conduit 9.

The end 9 of the conduit is fitted with a valve 11 the outlet of which is closed by a flange 12 The flange 12 is furnished with a device providing for closure of the valve 95 outlet and the temporary fitting of a lightening float 13.

The part of the body 5 situated remote from the conduit 1 bears on its end expandable means 14 for connecting the body 100 to a cable 15 Finally, the body 5 of the mooring head bears mooring means 16 which, in this embodiment, consist of a neck, the rim 17 of which constitutes an abutment surface cooperating with locking 1 i 5 means 18 fixed on a movable hollow arm 19 which will be described later on.

The mooring head 4 and, more particularly its body 5, bears a positioning projection 20 fitted in a manner to ensure 110 a precise angular positioning of the end 9 of the conduit 1.

A mooring frame, which secures the end of the conduit and allows its connection to a pipe of a fixed structure, comprises a 115 chassis 21 formed of an assembly of small girders made of metal or concrete which, according to the embodiment, forms a substantially rectangular base At least one part of the framework formed by the 120 girders has a floor 22 in its lower part consisting, for example, of a welded sheet of metal, thus forming troughs which will contain ballast, such as ballast blocks 23, after the frame has been positioned The 125 base has a shaft or plinth 24 in the centre of which a support column 25 is fitted The end of a fixed pipe 26 is attached to the upper end of the columns, on the axis thereof 130 1 591 931 The hollow arm 19 is moved in a cylindrical bearing block on the column 25 so as to be pivotable about the longitudinal axis of the column in a substantially horizontal plane through an angle of up to about 3600, this case of about 90 .

The hollow arm 19 consists of a cylindrical portion 27 extending from a conical portion 28 A strut 29 extends from one end to the other of the arm 19 on its lower part and in the direction of the axis thereof The end of the strut situated on the side of the conical portion 28 bears a skid cooperating with a part-annular track 31 fixed to the chassis 21 The strut 29 also serves for the fixing of a device with a stirrup 32 which allows the skid 30 to slide around the track 31 while at the same time preventing the surfaces of the skid 30 and track 31 from separating vertically The strut 29 and the device with the stirrup 32 have the object of ensuring that forces directed vertically upwards do not cause distortion of the arm 19 thus rendering useless the mooring device provided in the cylindrical part of the arm.

The arm 19 features on its upper part, adjacent its vertical axis of rotation, a cable guidance device 33 with a loose pulley 34 The cylindrical portion 27 of the arm is fitted internally with an abutment or stop 35 against which the end of the mooring head comes into contact, defining an exact position of the flange 12 borne by the mooring head with respect to the end of the fixed pipe 26.

The locking means 18 for the mooring head is mounted in a manner to project into the path of the mooring head A springloaded pivot device 36 allows the locking means to be raised during movement of the end of the head until the moment when the neck 16 comes opposite the locking means 18 which then swings and comes to rest against the neck The part connecting the conical portion 28 with the cylindrical portion 27 features a slot 37 (see Figure 2) the edges of which are substantially parallel to the generatrix of the conical portion.

This slot 37 cooperates with the positioning projection 20 fixed on the mooring head.

When the projection 20 is in place in the slot 37, the angular positioning of the end of the conduit is accurately determined.

The slot 37 has substantially parallel edges but is extended towards the opening of the conical portion 28 by edges diverging at such an angle that, when the mooring head is in place, the outer surface of the end 9 of the conduit is near the diverging edges, but not touching them, in order to prevent damage to the protective sheathing of the conduit.

The conical portion 28 has the object of assisting the introduction of the mooring head into the arm 19 and allowing its exact positioning.

A handling lug 38 permitting the placing of the arm on the column 25 and the track 31 is provided on the upper part of the 70 cylindrical body This operation of mounting the arm is carried out before submersion and obivously before fixing the pipe to the upper end of the column 25.

Fixing means 39 may be provided in 75 order to keep the arm in its final position when the conduit is moored, in order to avoid any movement which might be produced by underwater currents.

When the conduit 1 is moored and the 80 float 13 is freed, a junction duct (not shown) is connected to the flanges of the pipe and the conduit in order to effect the coupling of the conduit to the submarine structure, for example, a submerged storage 85 tank, the pipe 26 of which is fixed to the mooring frame According to a preferred shape, this junction duct has an inverted U shape so as to provide a certain amount of elasticity to compensate for 90 deviation due to constructional tolerances which can exist between the alignment of the junction duct flanges and the flanges of the pipe and the conduit.

The method of mooring a submarine 95 conduit as described above avoids the intervention of divers to complete the operation.

The submerging of the frame, as well as the connecting of the pipe 26, will not be 100 described in detail It suffices to know that the connecting of the pipe to the column of the arm can be done on the surface or at shallow depth, at the start, for example, of the construction of the structure 105 to be submerged which is to be connected to the conduit The frame is then submerged together with the structure If the frame is intended to be submerged at moderate depth, connection of the pipe can 110 be done by divers.

The frame is submerged, a hauling cable being wrapped around the pulley 34 and then passed into and through the cylindrical part of the arm to emerge from the open 115 ing of the conical portion 28 The two ends of this cable are kept on the surface.

The conduit 1, in hydrostatic equilibrium, equipped with a float system and guide rope as shown in Figure 1, is towed towards the 120 mooring frame The end of the conduit is brought to the surface or to a shallow depth where the attachment of the mooring head, described above, to the conduit and the connecting of the closing valve 11 125 are proceeded with The weight of the mooring head is compensated by the fitting of the float 13 which has also the object of keeping the outlet of the conduit in an attitude approximating to that which it 130 1 591 931 will have when moored One end of a towing cable is attached to the mooring head by the expandable fixing means 14, and the assembly of conduit and mooring head is submerged until it assumes a position substantially parallel to the sea bottom The other end of the towing cable is then attached, on the surface or at a shallow depth, to the end of the hauling cable which emerges from the cone of the arm The hauling cable is then wound in by a winch on the surface, drawing the towing cable until this is taken up by the winch and drags the mooring head, fixed to the conduit, into the conical portion 28 of the arm, and thus into the mooring position The expandable fixing means 14 are then actuated to free the towing cable 15 from the mooring head, the towing cable then being brought to the surface.

The lightening float 14 is freed and the junction duct is fixed in place between the conduit 9 and the pipe 26.

According to a variation of the method, the hauling cable has similar characteristics to the towing cable This allows the hauling cable to serve from the beginning of the operation simultaneously to tow the towing cable fixed to the mooring head and the conduit through the movable mooring arm.

The entry of the cable into the cone of the arm can take place over a wide range of directions, since the end of the arm moves on the back 31 to take up a position corresponding to the minimum frictional force of the cable against the cone and the body of the arm.

Claims

WI-IAT WE CLAIM IS:-

1 A device for use in coupling a submarine conduit to a submarine pipe, which device includes a mooring frame having a support column and a fastening hollow arm mounted on the column so as to be pivotable about the longitudinal axis of the column, and a mooring head adapted to be attached to the end of the conduit to be coupled to the pipe and to be drawn by a cable into the hollow arm, the hollow arm serving to automatically fasten the mooring head to the frame after taking up the position of least resistance to the cable.

2 A device according to claim 1, wherein the hollow arm has a cylindrical axial bore and the mooring head is substantially cylindrical and is adapted to fit within the bore.

3 A device according to claim 1 or 2, wherein the hollow arm includes a stop for positioning the mooring head at a predetermined distance from the support column.

4 A device according to any preceding claim, wherein the hollow arm is provided with locking means passing through a wall thereof for locking the mooring head within the hollow arm.

A device according to any preceding claim, wherein the positioning means are provided on the mooring head and the hollow arm for ensuring a particular orientation of the mooring head within the 70 hollow arm.

6 A device according to claim 5, wherein the positioning means comprises a longitudinal slot in the hollow arm and a projection on the mooring head adapted to fit 75 within the longitudinal slot.

7 A device according to any preceding claim, wherein the hollow arm is provided with a funnel-shaped end for assisting entry of the mooring head within the hollow arm 80

8 A device according to any preceding claim, wherein the mooring head is provided with expandable means for fixing the mooring head to a towing cable.

9 A device according to any preceding 85 claim, wherein the hollow arm is provided with cable guidance means for guiding the mooring head towing cable from the inside to the outside of the hollow arm.

A device according to claim 6 or 90 any one of claims 7 to 9 when appended directly or indirectly to claim 6, wherein the edges of the slot diverge towards the end of the hollow arm which is adapted to receive the mooring head so as to assist 95 entry of the projection on the mooring head into the slot and so as to enable the end of the conduit to project from the hollow arm.

11 A device according to any preceding 100 claim, wherein a strut extends along the length of the hollow arm.

12 A device according to any preceding claim, wherein the mooring head has an axial passage for accommodating the con 105 duit.

13 A device according to any preceding claimb, wherein the mooring head has an opening at its periphery through which the end of the conduit is intended to project 110

14 A device according to any preceding claim, wherein the mooring frame incorporates a base adapted to contain ballast.

A device according to claim 14, wherein the base is provided with a part 115 annular track and the hollow arm is provided with a skid which runs on the track.

16 A device according to claim 15, wherein means are provided for maintaining the skid in contact with the track 120

17 A device according to claim 15 or 16, wherein fixing means are provided for fixing the skid in its final position on the track when the mooring head is moored within the hollow arm 125

18 A device according to any preceding claim, wherein the mooring frame and mooring head are adapted to direct the end of the conduit substantially vertically upwards when the mooring head is within the 130 1 591 931 hollow arm.

19 A device according to any preceding claim, wherein the mooring frame is adapted to be secured to the pipe with the column coaxial with the end of the pipe to which the conduit is to be coupled.

The combination of a device according to any preceding claim and a float for attachment to the end of the conduit to be coupled to the pipe to maintain said end in hydrostatic equilibrium.

21 The combination of a device according to any one of claims 1 to 19 and a junction duct for connecting the conduit and the pipe.

22 The combination according to claim 21, wherein the junction duct is U-shaped.

23 A method of coupling a submarine conduit to a submarine pipe, which method comprises attaching a mooring frame having a support column to the pipe such that the pivot axis of a fastening hollow arm mounted on the column so as to be pivotable about the longitudinal axis of the column is coaxial with the end of the pipe to which the conduit is to be coupled, attaching a mooring head to the end of the conduit to which the pipe is to be coupled, and drawing the mooring head into the hollow arm by means of a cable coupled to the mooring head, the hollow arm automatically taking up the position of least resistance to the cable.

24 A method according to claim 23, further comprising connecting the conduit and the pipe by means of a junction duct.

A method according to claim 23 or 24, wherein the cable is passed over cable guide means on the hollow arm.

26 A method according to claim 25, wherein a towing cable is attached to the mooring head, a hauling cable is passed over the cable guiding means, one end of the hauling cable emerging from the end of the hollow arm adapted to receive the mooring head, the two ends of the hauling cable are held on the surface, the towing cable is attached to said one end of the hauling cable on the surface, the hauling cable is hauled by a winch until the towing cable reaches the winch, and the towing cable is then used to draw the mooring head into the hollow arm.

27 A method according to claim 25, wherein a hauling cable is passed over the 55 cable guiding means, one end of the hauling cable emerging from the end of the hollow arm adapted to receive the mooring head, the two ends of the hauling cable are held on the surface, and the hauling cable is 60 attached directly to the mooring head and used to draw the mooring head into the hollow arm.

28 A method according to claim 26 or 27, wherein the hauling cable is attached 65 to the towing cable or directly to the mooring head on the surface or at a shallow depth.

29 A method according to any one of claims 23 to 28, wherein the conduit is 70 brought to the surface or to a shallow depth for attachment of the mooring head.

A method according to any one of claims 23 to 29, wherein a float is attached to the end of the conduit to be coupled 75 to the pipe to maintain said end in hydrostatic equilibruim.

31 A method according to claim 24 or any one of claims 25 to 30 when appended to claim 24, wherein the mooring head is 80 locked within the hollow arm and the cable attached to the mooring head is released prior to connection of the junction duct.

32 A device for use in coupling a submarine conduit to a submarine pipe, which 85 device is substantially as hereinbefore described with reference to the accompanying drawings.

33 A method of coupling a submarine conduit to a submarine pipe, which method 90 is substantially as hereinbefore described with reference to the accompanying drawings.

ARTHUR R DAVIES, Chartered Patent Agents, 27, Imperial Square, Cheltenham, and 115, High Holborn, London, W C I.

Agents for the Applicants.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd, Berwick-upon-Tweed, 1981.

Published at the Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.

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